P4G isn't a bad reason, even if it's just to play through it then sell the Vita.
PS+ for Vita is okay. Mutant Blobs is gone now, so is JSR. Chronovolt is in and it sucks. RCR is in-- meh game with pretty funny nostalgia-stroking writing. You still get Uncharted, Wipeout, and Gravity Rush. The thing is, there doesn't seem to be a whole lot they could put up for Vita, so I'm thinking the offerings won't get much better over the course of this year, unless like every game on the system goes up for free.
buuuut you get PS+ for PS3 also, which is where the value really comes in.
I think it's a tough sell on Vita games alone, but fuck do I have a ton of PSP and PS1 games on there to sweeten the deal. I hadn't bought many PSP games on PSN before and was surprised to see how cheap they are.
as for the system itself, definitely one of my favorite designs ever. it's the system everyone dreamed of when the PSP came out--dual analogs on the go with console quality graphics. just terribly timed though.